I love them.

They're not without their flaws, but nonetheless, I'm thrilled with them.

I got them just for the minifigures, but I REALLY love the kits. Wasn't expecting that at all.

I've built 5 of the set so far. Here's what I've noticed flaws-wise for each (And surprisingly, big Optimus set has been the worst so far. So many errors, so many ambiguous instructions. I've had to take it apart and restart TWICE thanks to poor angles)

These are ones I've noticed. Yours may not have this problem, or it may be line-wide.

Common Problem - Humans with helmets. The helmets don't sit low enough compared to where the tampo'ed face details are. I've noticed this with all three of the helmeted humans I've opened so far. You'll see eyebrows and most of the eyes, but that's it. It also really seems like they did mean the helmet to go lower, as it sits a bit high. Alternatively, with Mirage, you'll see most of the sunglasses. It's less noticeable with Mirage's driver. I'm assuming this is a common, if not complete, error.

Common Difference - There's often a difference with the model you see on the front, to the model you make. Parts often go in different places, leading to a figure that can be noticeably different in places. Take note of which you'd prefer, and follow/ignore the instructions accordingly. Also, colours may vary. EG the colour of Ratchet's fists, plus numerous others. We're all used to that little disclaimer.

Large Optimus Prime set - Along with the human problems mentioned above for the 2 drivers included, note that there is a rather noticeable mistake with the stickers. Stickers meant for BLUE pieces have a BLACK background. This means they stand out, and is an obvious mistake. Also, make sure you really want to use the door stickers, as they look pretty bad once on, covering molded detail, and again, wrong colour background. (Note the box version has a painted stripe which avoids the molded panel, not possible with the sticker). They also advise you to place a sticker or two that doesn't exist, like the dual Autobot logo's on the bonnet in truck mode. There's only one.

Ratchet - The Ratchet Kreon's helmet covers his eyes. I've seen three examples with this defect so far, including my own, and the one showed at SDCC. It's an easy fix, just put a little tab of paper inside the helmet. This will give you enough height, and it should still click a little. This may or may not be a common problem.

Mirage - problem with the helmeted driver, however his sunglasses compensate for this a tad. Nothing else i noticed.

Prowl - Nothing that I noticed.

Small Bumblebee - Nothing that I noticed.

Overall, I still love them. But based on big Optimus so far, it seems the fun is LARGER with the smaller kits.

I also modded Prowl, to make him look more 'accurate', by moving his wheels to his shoulders, and moving his arm-lights up higher. I did this by only using left-over pieces from the same kit, and it looks great.